Oxidation of Carbon Monoxide by Perferrylmyoglobin

Autor(es)

Libardi, Silvia H. ^[1] ; Skibsted, Leif H. ^[2] ; Cardoso, Daniel R. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Copenhagen, Dept Food Sci, DK-1958 Frederiksberg C - Denmark

• Tipo de documento: Artigo Científico
• Fonte: Journal of Agricultural and Food Chemistry; v. 62, n. 8, p. 1950-1955, FEB 26 2014.
• Citações Web of Science: 2

Resumo

Perferrylmyoglobin is found to oxidize CO in aerobic aqueous solution to CO2. Tryptophan hydroperoxide in the presence of tetra(4-sulfonatophenyl)-porphyrinate-iron(III) or simple iron(II)/(III) salts shows similar reactivity against CO. The oxidation of CO is for tryptophan hydroperoxide concluded to depend on the formation of alkoxyl radicals by reductive cleavage by iron(II) or on the formation of peroxyl radicals by oxidative cleavage by iron(III). During oxidation of CO, the tryptophan peroxyl radical was depleted with a rate constant of 0.26 +/- 0.01 s(-1) for CO-saturated aqueous solution of pH 7.4 at 25 degrees C without concomitant reduction of the iron(IV) center. Carbon monoxide is as a natural metabolite accordingly capable of scavenging tryptophan radicals in myoglobin activated by peroxides with a second-order rate constant of (3.3 +/- 0.6) X 10(2) L mol(-1) s(-1), a reaction that might be of importance in cellular membranes of the intestine for protection of tissue against radical damage during meat digestion. (AU)

• Processo FAPESP: 11/51555-7 - Pão e carne para o futuro
• Beneficiário: Daniel Rodrigues Cardoso
• Modalidade de apoio: Auxílio à Pesquisa - Regular